EKGs pt 3 -- mechanical obstruction/STEMIs/SVTs
Have you ever died before?
(Jesus wept, Cassie, you’re a morbid fuck, you think. WHELP THERE’S A POINT TO IT…this time.)
((Also, I have recently had my Wellbutrin dose upped, thank you very much.))
So I’ve kinda-sorta died three times.
And I’ve got the photos to prove it.
This is why I’m on the EKG kick, because this post is scheduled to go live on 3/12, and if I time it right, you’ll be reading it while I’m in surgery to get an aberrant conduction pathway in my heart fixed. (It’s minor surgery, I’m sure I’ll be fine.)
Recapping:
Pt 1, we talked about how EKGs worked and the P-wave.
Pt 2, we talked about the QRS and T-wave, and then assorted heart blocks
And now we’re gonna talk about weird rhythms and what it feels like to kinda-sorta die.
So, briefly hopping back, we looked at what EKGs show when hearts behave erratically, but we didn’t really talk about what causes that behavior in the first place.
Usually, it’s a heart attack itself — some piece of cholesterol (a fatty deposit that accrues in the lining of your vasculature over time, this is why high cholesterol is bad for you) gets dislodged or the vessel gets so occluded that blood can no longer get through.
Cells that don’t have access to blood die. That’s just how it is — each of your cells always needs blood to bring it oxygen and sugar and to take waste and CO2 away.
So anything south of the occluded vessel, where ever it might be, is in trouble. And just like every other cell in your body — your heart cells require blood flow from its own pumping too! As those cells start to die, the beating of the heart is impaired, and the heart’s owner, depending on how bad things are, probably starts to feel pretty shitty.
So you go in. You’re clutching your chest, you’re feeling the elephant sitting on you, your left arm hurts (if you’re a dude, if you’re a lady, your constellation of symptoms can be far more nebulous, alas.) The tech puts an 12 lead EKG on you:
And you’re all wondering, WTF even is that? Because we haven’t even talked about half of the wave forms on this, the real deal. Here’s the cool shit/point of that though:
(Imagine laying this colored grid right on top of the EKG above!)
Because the 12 lead EKG is a 2D representation of the 3D goings on in your heart — a doctor can look at it and say, “WHOA. Lead V1 is really out of whack! That must be where your heart attack is actually occurring — in the septal region of your heart!”
It gives doctors a freaking map of where the damage is, and then they can hopefully take you to the cath lab and go up there and fix it for you. They can take out clots, they can put in stents (little tiny mesh support networks that hold vessels open from the inside so blood can pass through), or rewire your hearts vasculature entirely via a coronary artery bypass surgery (aka CABG) to get around the occluded zones (see below.)
And speaking of heart damage — let’s talk about STEMIs and tombstones:
A STEMI, which you might’ve heard overhead at a hospital as a STEMI-alert, stands for ST-elevation myocardial infarction. (Heart tissue is also called myocardial tissue, and infarction is tissue death.)
Basically a major artery to your heart is blocked.
Here’s an illustration of one:
And here’s one happening on an EKG, which’s got the ‘tombstone’ appearance:
I picked a pretty dramatic one so it’d be easier for you to see, but heart tissue is dying right there, all over that heart, you can see it on the page.
So now we know that heart damage comes in two flavors:
a) damage to the physical ability of the heart to operate, via clots that cut off the blood supply to its own tissue
b) the accrual of that damage taking out the heart nerves & tissue’s ability to conduct electrical impulses inside the heart, that also control the heart’s ability to beat at the right times.
What happens when hearts get hurt?
A bunch of different things can happen — you can go from a 1st degree heart block all the way up to a third (see prior post.)
If you hang around in a 3rd degree:
That’s not an organized rhythm, your just blood’s sloshing around in your heart like a 70’s waterbed, cells all over your body aren’t getting fed or oxygenated. You’re going to feel like shit (and almost certainly die if left untreated.)
Now your heart’s gonna start freaking out.
Because not only are you not sending blood all over your body to the rest of your cells — but you’re also not competently feeding the cells of your heart.
And as your heart starts to freak out about that fact, it might go into spasms.
Ventricular fibrillation looks like this:
(Even if you haven’t read the prior two posts, you can prolly tell shit ain’t right.)
I showed this clip awhile ago here, but it’s worth revisiting now that you have more context:
So if you play this clip, you’ll see two things — the heart muscle is vibrating uselessly, that’s the ventricular fibrillation occurring (aka v-fib) — and you’ll see the CPR that they’re doing on this patient. If you hang out and watch the whole thing you’ll hear the defibrillator charge with that sonic whine, and then see the muscle get zapped, after which it appears to go back into a normal rhythm.
It’s a great visual for how come v-fib is a useless (and deadly!) rhythm to be in. While your heart’s just doing a squiggle-line thing, blood isn’t moving anywhere, and you’re pretty much just dying. These people don’t have pulses, nor blood pressure, nothing’s happening, tissue is being lost.
You might’ve also heard a term called ‘pulseless v-tach’ — that’s when your heart’s doing this:
This is sliiiigghhhhtttly less shitty than v-fib.
If someone’s going in and out of this, you’re all, “Um, okay, let me side step over and get the crash cart juuusttt in case.”
(Sometimes older people’s hearts do loop-de-loos and they go in and out of this, but they spend more time normal than not. These people want pacemakers, usually, we’ll talk more about those later. And they’ll know something’s wrong, this rhythm doesn’t feel good.)
But if someone’s got this rhythm and no pulse, then it’s not doing them any good, blood isn’t going around — a pulse proves the mechanical blood-pumping-aspect of the heart is functioning.
Without a pulse, they’re gonna die, they need a shock.
Now onto what my heart does sometimes, and why I’m getting surgery.
My heart likes to pop into supraventricular tachycardia, aka SVT. This is when your heart gets trapped in an aberrant conduction pathway and the charges zip back and forth too fast to be good for you.
It looks like this:
(Imagine someone doing speed metal to Dragonforce, only it’s your heart beat instead.)
How fast can it get? I’ve clocked mine up to 240 before. Here’s me hanging out at 218 the other day. SIGH.
In and of itself, it’s highly unlikely to be fatal…but if it happens and you’re speed-metaling at 240 on the freeway and you pass out because you’re not getting enough blood flow to your head, that’s no bueno.
So what do you do to fix it?
Well, you can try doing vagal maneuvers, like trying to bear down and blow through a straw, to hopefully activate your vagus nerve into slowing your heart down.
But if that doesn’t work…one of the things they can do to fix it is to give you adenosine and stop your heart.
The text books tell you that getting adenosine feels like you’re dying.
I can tell you that they are 100% right!
What you’re looking at there is me getting adenosine about two weeks ago. It stops your heart for a few seconds and you basically feel like you’re gonna die. (I was rather pissed, I already had this surgery on the books, so I couldn’t believe my heart couldn’t just WAIT two more weeks before going back on its bullshit, but here we are.)
The only cool thing to come of this though is that I totally get why when men say they feel like they’ve got an elephant sitting on their chest during a heart attack, where that’s coming from, because I’ve felt it three times now too.
And what they’re feeling, IMO, is the cessation of blood pressure.
Like your heart is always beating, always moving blood forward — not having blood pressure feels a lot like the full-body-example of that BWAAAAAAA sound they used so much in the movie Inception, and it’s copycats thereafter.
Your body is all BWAAAAAA…like someone’s paused it. Like you’re full of static.
It feels like the edges of purgatory might, were I to believe in it, I think. Everything hurts and then — BAM! — your heart starts back up again and recedes into the background noise of your life, where it belongs.
Anyhow, heh — today a doctor’s putting a little catheter up my femoral and zapping my overzealous heart tissue and hopefully I won’t go into SVT again :P.
This email’s already too long (substack keeps warning me) so I’ll talk about bradycardias next week!
— Cassie